Data storage device using magnetic domain wall movement and method of operating the same

1. A data storage device, comprising: a magnetic layer including a plurality of magnetic domains and a magnetic domain wall present at a boundary of neighboring domains; a first ferromagnetic pinned layer formed on a lower surface of the magnetic layer; a second ferromagnetic pinned layer formed on a upper surface of the magnetic layer, the upper surface being opposite to the lower surface, wherein the first and second ferromagnetic pinned layers have opposite magnetization directions; a first insulating spacer interposed between the first ferromagnetic pinned layer and the magnetic layer; a second insulating spacer interposed between the second ferromagnetic pinned layer and the magnetic layer; and an energy supplying unit which applies energy to the magnetic layer to move the magnetic domain wall in the magnetic layer.

2. The data storage device of claim 1 , wherein the first and second ferromagnetic pinned layers are disposed on a portion of the respective lower and upper surfaces of the magnetic layer, the portion of the lower surface being corresponding to the portion of the upper surface.

3. The data storage device of claim 1 , wherein the first and second insulating spacers are an oxide layer.

4. The data storage device of claim 1 , wherein the energy to move the magnetic domain wall is a current or a magnetic field.

5. The data storage device of claim 1 , wherein the magnetic layer has two ends, at least one of which are connected to the energy supplying unit.

6. The data storage device of claim 5 , wherein the energy supplying unit is a transistor.

7. The data storage device of claim 1 , further comprising an anti-ferromagnetic layer, which is formed on a surface the first ferromagnetic pinned layer and/or the second ferromagnetic pinned layer in such a way that each of the first and the second ferromagnetic pinned layers is interposed between the anti-ferromagnetic layer and the magnetic layer.

8. The data storage device of claim 7 , wherein the anti-ferromagnetic layer is formed on the first ferromagnetic pinned layer and on the second ferromagnetic pinned layer.

9. The data storage device of claim 1 , further comprising: a laminate of a conductive spacer, a ferromagnetic pinned layer, and an anti-ferromagnetic layer, wherein the laminate is formed on a surface the first ferromagnetic pinned layer and/or the second ferromagnetic pinned layer in such a way that each of the first and the second ferromagnetic pinned layers is interposed between the laminate and the magnetic layer; and wherein the ferromagnetic pinned layer of the laminate has an opposite magnetization direction to a magnetization direction of the first ferromagnetic pinned layer or the second ferromagnetic pinned layer.

10. The data storage device of claim 9 , wherein the laminate is formed on the first ferromagnetic pinned layer and on the second ferromagnetic pinned layer.

11. A method of writing data onto a data storage device, which comprises: applying a writing voltage to the data storage device, the data storage device comprising: a magnetic layer including a plurality of magnetic domains and a magnetic domain wall present at a boundary of neighboring domains; a first ferromagnetic pinned layer formed on a lower surface of the magnetic layer; a second ferromagnetic pinned layer formed on a upper surface of the magnetic layer, the upper surface being opposite to the lower surface, wherein the first and second ferromagnetic pinned layers have opposite magnetization directions; a first insulating spacer interposed between the first ferromagnetic pinned layer and the magnetic layer; a second insulating spacer interposed between the second ferromagnetic pinned layer and the magnetic layer; and an energy supplying unit which applies energy to the magnetic layer to move the magnetic domain wall in the magnetic layer, wherein the writing voltage is applied between the first ferromagnetic pinned layer and the second ferromagnetic pinned layer to write data in the magnetic layer; and moving the magnetic domain wall of the magnetic layer by one bit.

12. A method of reading data in a data storage device, which comprises: measuring an electric resistance existing in the data storage device, the data storage device comprising: a magnetic layer including a plurality of magnetic domains and a magnetic domain wall present at a boundary of neighboring domains; a first ferromagnetic pinned layer formed on a lower surface of the magnetic layer; a second ferromagnetic pinned layer formed on a upper surface of the magnetic layer, the upper surface being opposite to the lower surface, wherein the first and second ferromagnetic pinned layers have opposite magnetization directions; a first insulating spacer interposed between the first ferromagnetic pinned layer and the magnetic layer; a second insulating spacer interposed between the second ferromagnetic pinned layer and the magnetic layer; and an energy supplying unit which applies energy to the magnetic layer to move the magnetic domain wall in the magnetic layer, wherein the electric resistance to be measured exists (i) between the first ferromagnetic pinned layer and one end of the magnetic layer, (ii) between the first ferromagnetic pinned layer and the other end of the magnetic layer, (iii) between the second ferromagnetic pinned layer and one end of the magnetic layer, (vi) between the second ferromagnetic pinned layer and the other end of the magnetic layer; and moving the magnetic domain wall of the magnetic layer by one bit.